Metal beverage cans have been commercially available equipped with easy opening facilities. Pull tabs and the like are now standard on such cans. U.S. Pat. No. 4,559,729 issued to R. G. White depicts and describes one common commercial tab structure.
Other examples of easy open can tops are described in U.S. Pat. Nos. 3,952,914; 3,738,526; 3,335,058 and 3,364,937.
While lip-opening covers made of thin plastic and the like have been suggested for coffee cup lids (e.g. U.S. Pat. No's. 4,113,155 and 4,190,174) such have not been successfully or practically incorporated into metal can tops due to the different problems and requirements for such cans. For example, cans must be made to resist accidental opening during storage, shipping or handling. The disposable plastic coffee cup type covers need not be similarly so concerned. Also the metal can's contents are often under internal pressure especially when they contain a carbonated beverage such as beer and most soft drinks and consequently a pressure proof closure must be provided. Again, coffee and tea cup covers are not concerned with that problem.